What is the main function of the heart during systole?

The main function of the heart during systole is to contract and pump blood throughout the body. During this phase of the cardiac cycle, the ventricles contract forcefully, which increases the pressure within them and pushes blood into the aorta and pulmonary artery from the left and right ventricles, respectively. This contraction is crucial for delivering oxygenated blood to the tissues and organs while also removing carbon dioxide and waste products.

In systole, the heart effectively moves blood from its lower chambers (the ventricles) into the systemic and pulmonary circulations, ensuring that the body receives the necessary nutrients and oxygen to function properly. This phase is essential for maintaining circulation and is characterized by the closing of the atrioventricular valves and the opening of the semilunar valves, which prevents backflow and directs blood into the arteries.

The other options describe phases or states that are characteristic of different parts of the cardiac cycle. For example, relaxation and filling of the heart with blood occur during diastole, which is the period following systole. A significant decrease in heart rate does not pertain directly to the active function of the heart during systole, and preparations for a resting state are associated with the heart completing its pumping cycle, transitioning back into diast